What do you mean by LVDT?

The LVDT is abbreviation of linear variable differential transformer. The LVDT is an inductive variable type displacement transducer. The circuit diagram of LVDT is as shown in below figure.

Linear Variable Differential Transformer (LVDT)

Construction of LVDT:

The linear variable differential transformer (LVDT) consist one primary and two secondary coils with a magnetic core free to move inside the coils. The output is the difference between emf produce by both secondary winding and hence it is known as differential output voltage. The core is generally made up of iron alloy. The core is positioned with non magnetic rod.

Working principle:

As per the position of core, the secondary coils e1 and e2 both produce emf which is opposite in phase. The lower end of both secondary coils e1 and e2 are joined together to get a differential output. According to the position of the core different conditions are formed.